Texts Won't delete

I have had this problem for a week or so now. I am unable to delete a text. I use chomp sms to text and it doesn't matter i go into the stock messaging app and it still refuses to delete them. All it does is deletes all the texts, send the thread to the bottom and has a time stamp of 12/31/1969 (why it's that date i have no idea). I have tried a couple third party apps to delete but they have failed as well. I took my phone to verizon and they said i may need to do a factory reset. I really don't wanna do that and lose all my stuff. I know you can use a recovery app but last time i used the app it took about 5 hours to get my phone back to normal

I had this same 12.31.1969 appear on my phone as an email. Amusingly at the time I was on a conspiracy/ Illuminati dedicated webpage. Mine deleted though. I must be down with the Death Star or something.